Presently known methods of determining the internal pressure of a gas bottle include the use of a pressure gauge. The gauge is connected to the outlet of the bottle prior to the operation of a value which allows the gauge to communicate directly with the contents of the bottle and respond to the pressure therein. Such gauges, whilst providing a high degree of accuracy, when correctly fitted by a skilled operator, do not lend themselves to the speedy operation. This can cause undesirable delays when an operator is checking a large number of bottles. In fact, the accuracy of such gauges can be an immaterial advantage when, for example, it is merely desired to check whether the bottle is substantially full or substantially empty, thereby to avoid an empty bottle being despatched to a customer.
There therefore exists a requirement for a method of and apparatus for determining the internal pressure of a sealed container, such as a bottle, which is comparatively quick to use and which does not rely on the skill of the operator to ensure an accurate measurement. An additional requirement which the present invention aims to achieve is to provide an apparatus which is easily accommodated in the relatively small gap between closely packed bottles.